Vulcanized adhesives are materials which are widely used to solidify the union between the parts which may be vulcanized rubber, vulcanized rubber with others which are not vulcanized, as well as rubber which may be vulcanized or not with other materials.
Traditionally, these adhesives contain elastomers such as natural rubber, styrene-butadiene copolymers, polychloroprene or similar polymers and additives to promote vulcanization, thickeners, and fillers, among others, that are mixed during the solid phases and then dissolved using solvents.
The solvents usually employed are mixtures comprising aromatic and aliphatic hydrocarbons, considered highly toxic, so they are replaced by other solvents, which cause less impact to the environment and human health and which has been a major inducement for research.
Substitution of aromatic and aliphatic solvents by natural solvents consisting of citrus terpenes and/or other natural terpenes such as d-limonene, terpinolenes, myrcene and linalool can be an alternative for the production of adhesives with a low toxicity. Moreover, these solvents are obtained from renewable sources and as co-products from the processes to extract juice for human consumption.
Within the scope of patents, some documents describe natural solvent based adhesive compositions and their use in methods for tire bonding.
Document U.S. 2003/0065080 describes resin coatings, adhesives and adhesive compositions comprising styrene copolymers and a terpene as a solvent and which are used for the manufacture of toys. This invention differs from that document because, among other technical reasons, it does not comprise styrene copolymers and it will not be used to manufacture toys, but tires.
Document U.S. Pat. No. 5,863,987 describes an adhesive composition used to manufacture tires comprising co-polymers of pyridine-styrene-butadiene, particles of latex and thermoset resin. This invention differs from that document because, among other technical reasons, it does not comprise copolymers of pyridine-styrene-butadiene and thermoset resin, and because it comprises natural solvents, a fact that is not mentioned in said document.
Document U.S. Pat. No. 6,136,123 describes an adhesive composition used to manufacture tires comprising a co-polymer of an acrylic acid ester and an organic peroxide. This invention differs from that document because, among other technical reasons, it does not comprise copolymers of an acrylic acid ester and an organic peroxide, and because it comprises natural solvents, a fact that is not mentioned in said document.
Document U.S. Pat. No. 4,497,927 describes an adhesive compound for the manufacture of tires comprising an oil-in-water emulsion with a continuous oily phase, in which a vulcanizable rubber compound is dissolved. This invention differs from that document because, among other technical reasons, it does not comprise an oil-in-water emulsion and because it comprises natural solvents, a fact that is not mentioned in said document.
What is clear from the literature researched, is that no prior documents were found suggesting the disclosures of this invention, so that the solution proposed herein, in the view of the inventors, is novel and has an inventive step in comparison with the prior art.